Enhanced high temperature coated superconductors joined at a cap layer

Abstract

This invention relates to a practical superconducting conductor based upon biaxially textured high temperature superconducting coatings. In particular, methods for producing flexible and bend strain-resistant articles and articles produced in accordance therewith are described which provide improved current sharing, lower hysteretic losses under alternating current conditions, enhanced electrical and thermal stability and improved mechanical properties between otherwise isolated films in a coated high temperature superconducting (HTS) wire. Multilayered materials including operational material which is sensitive to bend strain can be constructed, in which the bend strain in the region in which such operational material is located is minimized. The invention also provides a means for splicing coated tape segments and for termination of coated tape stack ups or conductor elements. In one embodiment, a multi-layer high temperature superconductor is provided and includes first and second high temperature superconductor coated elements. Each element includes a substrate, at least one buffer deposited on the substrate, a high temperature superconductor layer, and a cap layer. The first and second high temperature superconductor coated elements are joined at the first and second cap layers.

What is claimed is:  
     
       1. A multi-layer high temperature superconductor, comprising: 
       a first high temperature superconductor coated element, comprising:  
       a first substrate;  
       at least one first buffer deposited on the first substrate;  
       at least one first high temperature superconductor layer supported by the first buffer; and  
       a first metallic cap layer supported by the first high temperature superconductor layer; and  
       a second high temperature superconductor coated element, comprising:  
       a second substrate;  
       at least one second buffer deposited on the second substrate;  
       at least one second high temperature superconductor layer supported by the second buffer; and  
       a second metallic cap layer supported by the second high temperature superconductor layer;  
       wherein the first and second high temperature superconductor coated elements are joined at the first and second metallic cap layers.  
     
     
       2. The superconductor of  claim 1 , wherein the first substrate is biaxially textured. 
     
     
       3. The superconductor of  claim 2 , wherein the biaxial texturing is by deformation texturing. 
     
     
       4. The superconductor of  claim 3 , wherein the first substrate comprises nickel. 
     
     
       5. The superconductor of  claim 4 , wherein the first substrate comprises nickel-chromium, nickel-copper, or nickel-vanadium alloys. 
     
     
       6. The superconductor of  claim 5 , wherein the first substrate comprises a nickel-chromium alloy. 
     
     
       7. The superconductor of  claim 2 , wherein the at least one first buffer is epitaxially deposited. 
     
     
       8. The superconductor of  claim 1 , wherein the at least one first buffer comprises metal oxides. 
     
     
       9. The superconductor of  claim 8 , wherein the metal oxides comprise cerium oxide and gadolinium oxide. 
     
     
       10. The superconductor of  claim 8 , wherein the first buffer further comprises yttria stabilized zirconia. 
     
     
       11. The superconductor of  claim 1 , wherein at least two buffers are sequentially deposited on the first substrate. 
     
     
       12. The superconductor of  claim 11 , wherein three buffers are sequentially deposited on the first substrate. 
     
     
       13. The superconductor of  claim 1 , wherein the first high temperature superconductor layer comprises metal oxide. 
     
     
       14. The superconductor of  claim 1 , wherein the first high temperature superconductor layer comprises rare earth oxides. 
     
     
       15. The superconductor of  claim 14 , wherein the rare earth oxides have the formula (RE)Ba 2 Cu 3 O 7-δ , wherein RE is selected from the group consisting of rare earth elements and yttrium, and δ is a number greater than zero and less than one. 
     
     
       16. The superconductor of  claim 1 , wherein the first metallic cap layer is deposited on the first high temperature superconducting layer. 
     
     
       17. The superconductor of  claim 1 , wherein the first and second substrates are of substantially identical composition. 
     
     
       18. The superconductor of  claim 1 , wherein the first and second buffers are of substantially identical composition. 
     
     
       19. The superconductor of  claim 1 , wherein the first and second high temperature superconducting layers are of substantially identical composition. 
     
     
       20. The superconductor of  claim 1 , wherein the first and second metallic cap layers are of substantially identical composition. 
     
     
       21. The superconductor of  claim 1 , wherein the first and second high temperature superconductor coated elements are of substantially identical composition. 
     
     
       22. The superconductor of  claim 1 , wherein the first and second metallic cap layers are continuously joined at their uppermost surfaces. 
     
     
       23. The superconductor of  claim 1 , wherein the first and second metallic cap layers are a single continuous layer. 
     
     
       24. The superconductor of  claim 1 , wherein the superconductor is in the form of a tape. 
     
     
       25. The superconductor of  claim 1 , wherein the substrates are substantially untextured, and the buffers and high temperature superconductor layers are biaxially textured. 
     
     
       26. The superconductor of  claim 24 , wherein the first and second high temperature superconductor coated elements are registered at their respective edges. 
     
     
       27. The superconductor of  claim 24 , wherein the first and second high temperature superconductor coated elements are offset along their lengths. 
     
     
       28. The superconductor of  claim 27 , wherein at least one of the first and second metallic cap layers extends along the edge of at least the first and second high temperature superconductor coated element. 
     
     
       29. The superconductor of  claim 1 , wherein the superconductor comprises a multifilamentary structure. 
     
     
       30. The superconductor of  claim 29 , wherein the first and second high temperature superconducting layers are divided into a plurality of filaments. 
     
     
       31. The superconductor of  claim 1 , further comprising a stabilizer, wherein the first and second metallic cap layers are joined to opposing surfaces of the stabilizer. 
     
     
       32. The superconductor of  claim 1 , further comprising a solder layer positioned between the first and second metallic cap layers. 
     
     
       33. The superconductor of  claim 32 , wherein the first metallic cap layer is directly joined to the solder layer. 
     
     
       34. The superconductor of  claim 33 , wherein the second metallic cap layer is directly joined to the solder layer. 
     
     
       35. The superconductor of  claim 1 , wherein the first metallic cap layer comprises multiple layers. 
         36 .The superconductor of  claim 35 , wherein the multiple layers comprise: 
       a first metal layer; and  
       a second metal layer.  
     
     
       37. The superconductor of  claim 36 , wherein the first metal layer comprises silver and the second metal layer comprises copper. 
     
     
       38. The superconductor of  claim 35 , wherein the second metallic cap layer comprises: 
       a third metal layer; and  
       a fourth metal layer.  
     
     
       39. The superconductor of  claim 38 , wherein the third metal layer comprises silver and the fourth metal layer comprises copper.